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1.
JAC Antimicrob Resist ; 6(2): dlae053, 2024 Apr.
Article in English | MEDLINE | ID: mdl-38577702

ABSTRACT

Objectives: Antimicrobial resistance (AMR) in Neisseria gonorrhoeae is a global public health concern. Ceftriaxone is the last effective and recommended option for empirical gonorrhoea therapy worldwide, but several ceftriaxone-resistant cases linked to Asia have been reported internationally. During January 2022-June 2023, the WHO Enhanced Gonococcal Antimicrobial Surveillance Programme (EGASP) investigated N. gonorrhoeae AMR and epidemiological factors in patients from 10 clinical sentinel sites in Cambodia. Methods: Urethral swabs from males with urethral discharge were cultured. ETEST determined the MIC of five antimicrobials, and EGASP MIC alert values and EUCAST breakpoints were used. EGASP demographic, behavioural and clinical variables were collected using a standardized questionnaire. Results: From 437 male patients, 306 had positive N. gonorrhoeae cultures, AMR testing and complete epidemiological data. Resistance to ceftriaxone, cefixime, azithromycin and ciprofloxacin was 15.4%, 43.1%, 14.4% and 97.1%, respectively. Nineteen (6.2%) isolates were resistant to all four antimicrobials and, accordingly, categorized as XDR N. gonorrhoeae. These XDR isolates were collected from 7 of the 10 sentinel sites. No EGASP MIC alert values for gentamicin were reported. The nationally recommended cefixime 400 mg plus azithromycin 1 g (65.4%) or ceftriaxone 1 g plus azithromycin 1 g (34.6%) was used for treatment. Conclusions: A high prevalence of ceftriaxone-resistant, MDR and XDR N. gonorrhoeae in several cities of Cambodia were found during 2022-23 in WHO EGASP. This necessitates expanded N. gonorrhoeae AMR surveillance, revision of the nationally recommended gonorrhoea treatment, mandatory test of cure, enhanced sexual contact notification, and ultimately novel antimicrobials for the treatment of gonorrhoea.

2.
Phys Rev Lett ; 132(5): 056201, 2024 Feb 02.
Article in English | MEDLINE | ID: mdl-38364151

ABSTRACT

We use photoemission electron microscopy to measure the ferroelastic twin wall angles at the surface of CaTiO_{3} (001) and deduce the strain ordering. We analyze the angular dependence of the photoelectron emission from different domain surfaces, each with its own characteristic tilt angle in the factory rooflike topography. By considering the surface topography as a field perturbation, the offset in the photoemission threshold can be directly related to the tilt angles. With knowledge of the symmetry allowed twin walls we quantify the twin angles between 179.1° to 180.8°.

3.
Ultramicroscopy ; 253: 113814, 2023 Nov.
Article in English | MEDLINE | ID: mdl-37515931

ABSTRACT

A two-dimensional imaging spin-filter for photo-emission electron microscopy is described. The spin-filter is capable of imaging the electron spin polarization of either real space or momentum space electron distributions. As a scattering target either Au/Ir(001) comes into use, where spin sensitivity results from using spin-orbit scattering or Fe(001)-p(1×1)O that exploits exchange interaction. Both scattering targets were characterized with respect to their working points and Sherman function in a separate setup. Spin-polarization images of secondary electrons from the magnetic domains of a poly-crystalline iron sample are shown using both scattering targets. Images with a spin-filter using Au/Ir(001) show more than 104 discrete detection channels which increases the effective two-dimensional figure-of-merit (FoM) of this spin-filter by four orders of magnitude compared to single-channel spin detectors. Using the exchange scattering target two spin-components have been imaged for the first time. A method to detect all three spin-components is also outlined.

4.
NeuroRehabilitation ; 41(3): 627-637, 2017.
Article in English | MEDLINE | ID: mdl-29036847

ABSTRACT

OBJECTIVE: To generate normative data for the Trail Making Test (TMT) in Spanish-speaking pediatric populations. METHOD: The sample consisted of 3,337 healthy children from nine countries in Latin America (Chile, Cuba, Ecuador, Guatemala, Honduras, Mexico, Paraguay, Peru, and Puerto Rico) and Spain. Each participant was administered the TMT as part of a larger neuropsychological battery. The TMT-A and TMT-B scores were normed using multiple linear regressions and standard deviations of residual values. Age, age2, sex, and mean level of parental education (MLPE) were included as predictors in the analyses. RESULTS: The final multiple linear regression models showed main effects for age on both scores, such that as children needed less time to complete the test while they become older. TMT-A scores were affected by age2 for all countries except, Cuba, Guatemala, and Puerto. TMT-B scores were affected by age2 for all countries except, Guatemala and Puerto Rico. Models indicated that children whose parent(s) had a MLPE >12 years of education needed less time to complete the test compared to children whose parent(s) had a MLPE ≤12 years for Mexico and Paraguay in TMT-A scores; and Ecuador, Mexico, Paraguay, and Spain for TMT-B scores. Sex affected TMT-A scores for Chile, Cuba, Mexico, and Peru, in that boys needed less time to complete the test than girls. Sex did not affect TMT-B scores. CONCLUSIONS: This is the largest Spanish-speaking pediatric normative study in the world, and it will allow neuropsychologists from these countries to have a more accurate approach to interpret the TMT in pediatric populations.


Subject(s)
Language , Trail Making Test/standards , Child , Humans , Latin America , Reference Values
5.
NeuroRehabilitation ; 41(3): 695-706, 2017.
Article in English | MEDLINE | ID: mdl-29036849

ABSTRACT

OBJECTIVE: To generate normative data for the Learning and Verbal Memory Test (TAMV-I) in Spanish-speaking pediatric populations. METHOD: The sample consisted of 4,373 healthy children from nine countries in Latin America (Chile, Cuba, Ecuador, Guatemala, Honduras, Mexico, Paraguay, Peru, and Puerto Rico) and Spain. Each participant was administered the TAMV-I as part of a larger neuropsychological battery. Free recall, memory delay and recognition scores were normed using multiple linear regressions and standard deviations of residual values. Age, age2, sex, and mean level of parental education (MLPE) were included as predictors in the analyses. RESULTS: The final multiple linear regression models indicated main effects for age on all scores, such that scores increased linearly as a function of age. Age2 had a significant effect in all countries except Cuba, and Puerto Rico for free recall score; a significant effect for memory delay score in all countries except Cuba and Puerto Rico; and a significant effect for recognition score in in all countries except Guatemala, Honduras, and Puerto Rico. Models showed an effect for MLPE in Chile (free recall), Honduras (free recall), Mexico (free recall), Puerto Rico (free recall, memory delay, and recognition), and Spain (free recall and memory delay). Sex affected free recall score for Cuba, Ecuador, Guatemala, Mexico, Paraguay, Peru, and Spain, memory delay score for all countries except Chile, Paraguay, and Puerto Rico, and recognition score for Ecuador, Mexico, Peru, and Spain, with girls scoring higher than boys. CONCLUSIONS: This is the largest Spanish-speaking pediatric normative study in the world, and it will allow neuropsychologists from these countries to have a more accurate way to interpret the TAMV-I with pediatric populations.


Subject(s)
Hispanic or Latino , Language , Memory and Learning Tests , Child , Cultural Competency , Female , Humans , Latin America , Male
6.
NeuroRehabilitation ; 41(3): 673-686, 2017.
Article in English | MEDLINE | ID: mdl-28946591

ABSTRACT

OBJECTIVE: To generate normative data for the phonological and semantic verbal fluency tests (VFT) in Spanish-speaking pediatric populations. METHOD: The sample consisted of 4,373 healthy children from nine countries in Latin America (Chile, Cuba, Ecuador, Guatemala, Honduras, Mexico, Paraguay, Peru, and Puerto Rico) and Spain. Each participant was administered the VFT as part of a larger neuropsychological battery. Scores for letters F, A, S, and animals and fruit categories were normed using multiple linear regressions and standard deviations of residual values. Age, age2, sex, and mean level of parental education (MLPE) were included as predictors in the analyses. RESULTS: The final multiple linear regression models showed main effects for age on all scores, such that scores increased linearly as a function of age. Age2 had a significant effect in Chile (animals), Cuba (A letter, fruits), Ecuador (animals, fruits), Honduras (F letter), Mexico (animals, fruits), Peru (fruits), and Spain (S letters, animals, fruits). Models showed an effect for MLPE in Chile (A letters, animals, fruits), Ecuador (S letter, animals, fruits), Guatelama (F, S letter, animals), Honduras (animals), Mexico (F, A, S letters, animals, fruits), Puerto Rico (A, letters, animals), and Spain (all scores). Sex scores were found significant in Chile (animals), Ecuador (A letter, fruits), Mexico (F letter, fruits), Paraguay (F, A, S letters, fruits), Puerto Rico (F letter, animals, fruits), and Spain (F letter, fruits). CONCLUSIONS: This is the largest multi-national Spanish speaking-pediatric normative study in the world, and as such it will allow neuropsychologists from these countries to have a more accurate way to interpret the phonological and semantic VFT in pediatric populations.


Subject(s)
Language Tests/standards , Child , Humans , Language , Latin America , Spain
7.
NeuroRehabilitation ; 41(3): 605-616, 2017.
Article in English | MEDLINE | ID: mdl-28946595

ABSTRACT

OBJECTIVE: To generate normative data for the Stroop Word-Color Interference test in Spanish-speaking pediatric populations. METHOD: The sample consisted of 4,373 healthy children from nine countries in Latin America (Chile, Cuba, Ecuador, Guatemala, Honduras, Mexico, Paraguay, Peru, and Puerto Rico) and Spain. Each participant was administered the Stroop Word-Color Interference test as part of a larger neuropsychological battery. The Stroop Word, Stroop Color, Stroop Word-Color, and Stroop Interference scores were normed using multiple linear regressions and standard deviations of residual values. Age, age2, sex, and mean level of parental education (MLPE) were included as predictors in the analyses. RESULTS: The final multiple linear regression models showed main effects for age on all scores, except on Stroop Interference for Guatemala, such that scores increased linearly as a function of age. Age2 affected Stroop Word scores for all countries, Stroop Color scores for Ecuador, Mexico, Peru, and Spain; Stroop Word-Color scores for Ecuador, Mexico, and Paraguay; and Stroop Interference scores for Cuba, Guatemala, and Spain. MLPE affected Stroop Word scores for Chile, Mexico, and Puerto Rico; Stroop Color scores for Mexico, Puerto Rico, and Spain; Stroop Word-Color scores for Ecuador, Guatemala, Mexico, Puerto Rico and Spain; and Stroop-Interference scores for Ecuador, Mexico, and Spain. Sex affected Stroop Word scores for Spain, Stroop Color scores for Mexico, and Stroop Interference for Honduras. CONCLUSIONS: This is the largest Spanish-speaking pediatric normative study in the world, and it will allow neuropsychologists from these countries to have a more accurate approach to interpret the Stroop Word-Color Interference test in pediatric populations.


Subject(s)
Stroop Test/standards , Child , Female , Humans , Latin America , Linear Models , Male
8.
Internist (Berl) ; 58(9): 982-989, 2017 Sep.
Article in German | MEDLINE | ID: mdl-28271269

ABSTRACT

A 20-year-old woman presented with acute exacerbation of ulcerative colitis. After treatment with infliximab, she developed a fulminant liver failure. Under supportive therapy and steroid medication, recovery of symptoms and transaminases occurred. A few case reports about hepatic side effects of anti-TNF-α antibodies in patients with inflammatory bowel disease have been published. These side effects ranged from asymptomatic increase of transaminases to fulminant liver failure necessitating transplantation. The pathomechanism is not fully understood; in some case reports autoimmune phenomena have been described.


Subject(s)
Colitis, Ulcerative/drug therapy , Infliximab/adverse effects , Infliximab/therapeutic use , Liver Failure, Acute/chemically induced , Colitis, Ulcerative/diagnosis , Diagnosis, Differential , Disease Progression , Drug Therapy, Combination , Female , Humans , Hydrocortisone/therapeutic use , Infusions, Intravenous , Liver Failure, Acute/diagnosis , Liver Function Tests , Prednisolone/therapeutic use , Sigmoidoscopy , Tacrolimus/adverse effects , Tacrolimus/therapeutic use , Tomography, X-Ray Computed , Young Adult
9.
Rev Sci Instrum ; 85(11): 113704, 2014 Nov.
Article in English | MEDLINE | ID: mdl-25430117

ABSTRACT

Hard x-ray photoelectron spectroscopy (HAXPES) has now matured into a well-established technique as a bulk sensitive probe of the electronic structure due to the larger escape depth of the highly energetic electrons. In order to enable HAXPES studies with high lateral resolution, we have set up a dedicated energy-filtered hard x-ray photoemission electron microscope (HAXPEEM) working with electron kinetic energies up to 10 keV. It is based on the NanoESCA design and also preserves the performance of the instrument in the low and medium energy range. In this way, spectromicroscopy can be performed from threshold to hard x-ray photoemission. The high potential of the HAXPEEM approach for the investigation of buried layers and structures has been shown already on a layered and structured SrTiO3 sample. Here, we present results of experiments with test structures to elaborate the imaging and spectroscopic performance of the instrument and show the capabilities of the method to image bulk properties. Additionally, we introduce a method to determine the effective attenuation length of photoelectrons in a direct photoemission experiment.

11.
Epidemiol Infect ; 142(12): 2559-66, 2014 Dec.
Article in English | MEDLINE | ID: mdl-24534429

ABSTRACT

We describe a foodborne outbreak in Italy caused by enteroinvasive Escherichia coli (EIEC), an enteric pathogen uncommon in industrialized countries. On 14 April 2012 a number of employees of the city of Milan Fire Brigade (FB) were admitted to hospital with severe diarrhoea after attending their canteen. Thirty-two patients were hospitalized and a total of 109 cases were identified. A case-control study conducted on 83 cases and 32 controls attending the canteen without having symptoms identified cooked vegetables to be significantly associated with the disease. Stool samples collected from 62 subjects were screened for enteric pathogens using PCR-based commercial kits: 17 cases and two asymptomatic kitchen-workers were positive for the Shigella marker gene ipaH; an ipaH-positive EIEC strain O96:H19 was isolated from six cases. EIEC may cause serious dysentery-like outbreaks even in Western European countries. Microbiologists should be aware of microbiological procedures to detect EIEC, to be applied especially when no common enteric pathogens are identified.


Subject(s)
Diarrhea/epidemiology , Disease Outbreaks , Dysentery, Bacillary/epidemiology , Escherichia coli Infections/epidemiology , Escherichia coli/isolation & purification , Foodborne Diseases/epidemiology , Shigella/isolation & purification , Acute Disease , Adult , Bacterial Typing Techniques/methods , Case-Control Studies , Diarrhea/microbiology , Dysentery, Bacillary/microbiology , Escherichia coli Infections/microbiology , Feces/microbiology , Female , Foodborne Diseases/microbiology , Humans , Italy/epidemiology , Male , Middle Aged , Polymerase Chain Reaction , Vegetables/microbiology
13.
Euro Surveill ; 18(18): 20472, 2013 May 02.
Article in English | MEDLINE | ID: mdl-23725775

ABSTRACT

Two gendarmes who participated in canyoning activities on 27 June 2011 on the Caribbean island of Martinique were diagnosed with leptospirosis using quantitative real-time polymerase chain reaction (qPCR), 9 and 12 days after the event. Among the 45 participants who were contacted, 41 returned a completed questionnaire, of whom eight met the outbreak case definition. The eight cases sought medical attention and were given antibiotics within the first week after fever onset. No severe manifestations of leptospirosis were reported. In seven of the eight cases, the infection was confirmed by qPCR. Three pathogenic Leptospira species, including L. kmetyi, were identified in four of the cases. None of the evaluated risk factors were statistically associated with having developed leptospirosis. Rapid diagnostic assays, such as qPCR, are particularly appropriate in this setting ­ sporting events with prolonged fresh-water exposure ­ for early diagnosis and to help formulate public health recommendations. Participants in such events should be made specifically aware of the risk of leptospirosis, particularly during periods of heavy rainfall and flooding.


Subject(s)
Disease Outbreaks , Leptospira/isolation & purification , Leptospirosis/epidemiology , Mountaineering , Adult , Female , Humans , Leptospirosis/diagnosis , Leptospirosis/prevention & control , Male , Martinique/epidemiology , Middle Aged , Patient Acceptance of Health Care/psychology , Patient Acceptance of Health Care/statistics & numerical data , Real-Time Polymerase Chain Reaction , Risk Factors , Sensitivity and Specificity , Surveys and Questionnaires , Time Factors , Young Adult
14.
Dtsch Med Wochenschr ; 137(6): 260-4, 2012 Feb.
Article in German | MEDLINE | ID: mdl-22294110

ABSTRACT

HISTORY AND ADMISSION FINDINGS: A 19-year-old HIV-positive man was admitted with fever of unknown origin and poor general condition. Antiretroviral therapy had been stopped by the patient eight months prior to admission. INVESTIGATIONS: Laboratory tests revealed pancytopenia, high viral load and low count of T-helper cells (13/µl). Computer tomography of the thorax showed small patchy infiltrations. Extensive examinations (microbiology, laboratory tests, multiple investigations) revealed no pathogen. Liver biopsy proved disseminated histoplasmosis. TREATMENT AND COURSE: Liposomal amphotericin B was started and switched to oral itraconazole after 14 days with itraconazole. With this treatment the patient condition improved and fever stopped. T-helper cells increased and the patient was discharged. CONCLUSION: Disseminated histoplasmosis as an AIDS-defining opportunistic infection is uncommon (particularly as the patient had not been abroad in the last four years) and can be a life-threatening complication. Diagnosis must be confirmed by invasive methods especially in patients with compromised immune status and rapid clinical progression.


Subject(s)
AIDS-Related Opportunistic Infections/diagnosis , Histoplasmosis/diagnosis , AIDS-Related Opportunistic Infections/drug therapy , Amphotericin B/therapeutic use , Anti-Bacterial Agents/therapeutic use , Anti-HIV Agents/therapeutic use , Antifungal Agents/therapeutic use , Antiretroviral Therapy, Highly Active , Biopsy , Bronchoscopy , Diagnosis, Differential , Drug Therapy, Combination , Histoplasmosis/drug therapy , Humans , Infusions, Intravenous , Liver/pathology , Male , Tomography, X-Ray Computed , Young Adult
15.
J Crohns Colitis ; 4(5): 606-9, 2010 Nov.
Article in English | MEDLINE | ID: mdl-21122569

ABSTRACT

Here we report 2 cases of fatal Pneumocystis jirovecii pneumonia in patients with severe ulcerative colitis receiving combination immunosuppression including tacrolimus. We discuss the necessity of a P. jirovecii prophylaxis especially in elderly patients according to the European evidence-based consensus on the prevention and management of opportunistic infections in inflammatory bowel disease.


Subject(s)
Colitis, Ulcerative/complications , Colitis, Ulcerative/drug therapy , Immunosuppression Therapy/adverse effects , Immunosuppressive Agents/adverse effects , Opportunistic Infections/complications , Pneumocystis carinii/isolation & purification , Pneumonia, Pneumocystis/complications , Tacrolimus/adverse effects , Aged , Colitis, Ulcerative/immunology , Colitis, Ulcerative/microbiology , Fatal Outcome , Humans , Male , Opportunistic Infections/diagnosis , Opportunistic Infections/immunology , Pneumonia, Pneumocystis/diagnosis , Pneumonia, Pneumocystis/immunology , Risk Factors
16.
Rev Sci Instrum ; 81(4): 043304, 2010 Apr.
Article in English | MEDLINE | ID: mdl-20441333

ABSTRACT

We have developed an energy analyzer, High Voltage-Cylinder Sector Analyzer 300/15, for electron kinetic energies up to 15 keV. It is especially suited for hard x-ray photoelectron spectroscopy, but also for ultraviolet and soft x-ray photoelectron spectroscopy (ultraviolet photoemission spectroscopy, x-ray photoemission spectroscopy), Auger electron spectroscopy, and reflection high energy electron spectroscopy. The analyzer is based on a cylinder sector with 90 degrees deflection, 300 mm slit-to-slit distance, and a four-element pre-retarding lens system with 50 mm sample-to-lens distance. The result is a very compact design of the analyzer that is easily integrated into a multipurpose experiment with different techniques. A low noise/low drift electronics is capable of continuous energy scans from 0 to 15 keV using nonlinear lens curves. The first analyzer is allocated at the Spanish CRG SpLine beamline at the ESRF at an end station where simultaneous surface x-ray diffraction is possible. The analyzer is operated routinely since 2006 up to 15 keV electron kinetic energy, expanding the achievable electron kinetic energy range compared to other commercial analyzers. In this work we present a detailed description of the developed electron analyzer. The analyzer capabilities, in terms of energy resolution and transmission, are shown by using an electron gun, an ultraviolet-discharge lamp, and hard x-ray synchrotron radiation as excitation sources.

17.
Crit Care Med ; 37(2): 528-32, 2009 Feb.
Article in English | MEDLINE | ID: mdl-19114900

ABSTRACT

OBJECTIVE: When a patient is incompetent, the family is often considered to be a natural surrogate. The doctors' responsiveness to family wishes may vary. We explored if doctors' personal characteristics were associated with responsiveness to the relatives' wishes when admission to the intensive care unit (ICU) is considered. METHODS: In a mail survey, we asked all Swiss ICU doctors to decide on the admission of a hypothetical incompetent patient presenting with hemolytic uremic syndrome. Each participant was randomly allocated to a version of the scenario in which the family asked either that "everything be done" or that the patient be "spared useless suffering." MAIN RESULTS: Overall, 232 (60.9%) questionnaires were returned. When the family asked that "everything be done," 60% of doctors chose to admit the hypothetical patient, but when the family asked that she be spared useless suffering, only 39% did so (odds ratio [OR] 2.6, confidence interval 1.5-4.6). This OR captures responsiveness to family wishes. It varied across subgroups of ICU doctors. Characteristics associated with greater responsiveness to family wishes were older age (OR 6.0 vs. 1.2, p = 0.002), nonuniversity work setting (OR 4.2 vs. 1.0, p = 0.012), less time devoted to intensive care practice (OR 4.0 vs. 1.5, p = 0.036), and greater self-confidence in ethical knowledge (OR 3.4 vs. 1.7, p = 0.044). CONCLUSIONS: Older doctors and those working in regional hospitals were more responsive to family wishes when assessing an incompetent patient for ICU admission. These findings emphasize the need for effective advance care planning.


Subject(s)
Decision Making , Intensive Care Units , Mental Competency , Patient Admission , Physicians , Professional-Family Relations , Adult , Female , Health Care Surveys , Humans , Male , Middle Aged , Surveys and Questionnaires , Switzerland , Triage
18.
J Phys Condens Matter ; 21(31): 314002, 2009 Aug 05.
Article in English | MEDLINE | ID: mdl-21828563

ABSTRACT

Lateral resolution is a major issue in photoelectron emission microscopy (PEEM) and received much attention in the past; however a reliable practical methodology allowing for inter-laboratory comparisons is still lacking. In modern, energy-filtered instruments, core level or valence electrons give much lower signal levels than secondary electrons used in still most of the present experiments. A quantitative measurement of the practical resolution obtained with core level electrons is needed. Here, we report on critical measurements of the practical lateral resolution measured for certified semiconducting test patterns using core level photoelectrons imaged with synchrotron radiation and an x-ray PEEM instrument with an aberration-corrected energy filter. The resolution is 250 ± 20 nm and the sensitivity, 38 nm. The different contributions to the effective lateral resolution (electron optics, sample surface imperfections, counting statistics) are presented and quantitatively discussed.

19.
Rev Sci Instrum ; 79(5): 053702, 2008 May.
Article in English | MEDLINE | ID: mdl-18513070

ABSTRACT

We demonstrate the use of a novel design of a photoelectron microscope in combination to an imaging energy filter for momentum resolved photoelectron detection. Together with a time resolved imaging detector, it is possible to combine spatial, momentum, energy, and time resolution of photoelectrons within the same instrument. The time resolution of this type of energy analyzer can be reduced to below 100 ps. The complete ARUPS pattern of a Cu(111) sample excited with He I, is imaged in parallel and energy resolved up to the photoelectron emission horizon. Excited with a mercury light source (h nu=4.9 eV), the Shockley surface state at the energy threshold is clearly imaged in k-space. Electron-electron interactions are observed in momentum space as a correlation hole in two-electron photoemission. With the high transmission and the time resolution of this instrument, possible new measurements are discussed: Time and polarization resolved ARUPS measurements, probing change of bandstructure due to chemical reaction, growth of films, or phase transitions, e.g., melting or martensitic transformations.

20.
J Microsc ; 206(Pt 2): 132-8, 2002 May.
Article in English | MEDLINE | ID: mdl-12000552

ABSTRACT

An emission electron microscope was used for visualization and measurement of the distribution of electric fields and potentials on the surface under study. The contrast of microfields is caused by the fact that slow-moving electrons emitted from the object surface are deflected by these fields. The measurements were performed on a p-n junction to which a voltage was applied. It is shown that the type of contrast from the p-n junction can be reversed depending on the position of the contrast aperture restricting the electron beam. The same result was obtained by means of a computer simulation.

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